If the diameter of a carbon atom is $0.15 \,nm$,calculate the number of carbon atoms which can be placed side by side in a straight line across the length of a scale of length $20 \,cm$.

What is $NTP$ or $STP$ and $SATP$? Mention their molar volumes.

Fill in the blanks given below:
$(i)$ At ........ ${\,^\circ }{\text{C}}$,the values of temperature in both ${\,^\circ }{\text{C}}$ and ${\,^\circ }{\text{F}}$ are equal.
$(ii)$ The number of significant figures in $0.03$ is .....
$(iii)$ The closeness of various measurements for the same quantity is called .........
$(iv)$ The agreement of a particular value to the true value of the result is called ....

The units nanometer and picometer are related as,

Choose the correct statements.
$A$. Weight of a substance is the amount of matter present in it.
$B$. Mass is the force exerted by gravity on an object.
$C$. Volume is the amount of space occupied by a substance.
$D$. Temperatures below $0^{\circ} C$ are possible in Celsius scale,but in Kelvin scale negative temperature is not possible.
$E$. Precision refers to the closeness of various measurements for the same quantity.

$5 \times 10^2 \, cm = .......... \, dm$